北京市4种不同污水处理系统中病原菌变化研究

采用定量PCR技术,对北京市4种不同污水处理系统中大肠杆菌、军团菌和沙门氏菌随工艺及四季的数量变化进行了追踪研究,以评估病原菌的去除效果及污水回用的健康风险.结果发现,大肠杆菌在夏季进水和出水中的浓度分别在107~108copies·m L-1和105copies·m L-1左右;G-A/O系统对大肠杆菌的去除率最高,平均去除率达99.88%.军团菌在4个污水处理系统中进水浓度为104~105copies·m L-1,出水浓度约为104copies·m L-1,其在剩余污泥样品中浓度较高,达到105~106copies·m L-1.沙门氏菌进水浓度较低,为102~103copies·m L-1,且其在多个工艺段样品中未检出.季节变化对于病原菌的去除具有较大影响.研究表明,大肠杆菌在各污水处理系统中均可检出,且其分布具有一定的季节性,夏季的进出水中浓度相对较高;而军团菌和沙门氏菌浓度在各工艺中则并未呈现出明显的季节性变化.G-A/O系统对3种细菌的整体去除效果最为稳定,去除率较高.大肠杆菌在污水处理厂的出水及剩余污泥中浓度仍然较高,此外,冬季出水中也能检测到沙门氏菌的存在,因此,污水处理厂的出水和污泥排放仍存在一定的生态和健康风险.

The varity regulation of pathogens in the different process of four wastewater treatment plants in Beijing

To evaluate the removal efficiency of pathogens and the health risks of sewage reuse, the distribution and abundance of the three pathogens were investigated in different Wastewater Treatment Plants with seasons. The quantitative PCR (qPCR) technology was adopted.The result showed that E.coli can be detected in all samples. Compared with other seasons, summer has the highest concentrations of E.coli in influent (10⁷~10⁸ copies · mL^-1) and effluent (10⁵ copies · mL^-1). The G-A/O process has the highest removal rate, which was 99.88%. The concentrations of Legionella in the four Wastewater Treatment Plants were 10⁴~10⁵ copies · mL^-1 in influent, about 10⁴ copies · mL^-1 in effluent, and 10⁵~10⁶ copies · mL^-1 in the return sludge. The Salmonella was 10²~10³ copies · mL^-1 in the influent and was not found in most other wastewater treatment processes, lower than other pathogens. Season changes could lead to an important effect on pathogens removal. E.coli can be detected in all samples and the concentration changed with season, which was relatively higher in influent and effluent in summer; while the same phenomenon was not found in Legionella and Salmonella. The G-A/O system showed a stable and efficient removal of E.coli, Legionella and Salmonella. A high concentration of E.coli was detected in the excess sludge and effluent, and Salmonella was also found in effluent in winter. So there are still some ecological and healthy risks of effluent and excess sludge discharged from the Wastewater Treatment Plants.